Switching farms from cows to crops could increase emissions - expert
Switching farms from cows to crops or feeding animals seaweed are not going to provide silver bullet solutions to Ireland’s biggest greenhouse gas problem, farming experts have said.
Swopping the national dairy herd – the country’s single biggest producer of carbon emissions – for tillage fields could even increase emissions by ploughing up carbon stored in the soil for centuries.
Experts gathering in Dublin to discuss dairy and climate change warned that some of the ideas being put forward as solutions to the sector’s emissions were overly simplistic.
Professor Gary Lanigan, a greenhouse gas scientist, said changing the diet of cows to reduce the amount of methane gas they produce was being studied but the results were mixed.
“The seaweed idea has merit but you need an awful lot of it. You can add nitrates to the diet but there’s a danger of killing the animal from nitrogen poison. You can feed them urea but that creates ammonia which causes a pollution issue,” he said.
“There have been programmes, particularly in New Zealand, looking for silver bullets for the past 20-30 years and they haven’t found any yet.”
Agriculture is responsible for a third of Ireland’s greenhouse gas emissions and dairy is by far the biggest contributor. National policy is to increase the dairy herd further but environmentalists have called for a halt in the expansion and a possible switch to crop production.
Prof Lanigan said there was no easy answer in that route either as the permanent grasslands that support the dairy sector are natural carbon stores. “If we were to double our tillage area we would release somewhere in the region of 345 tonnes of CO2 which is equivalent to about 100,000 cows,” he said.
Dr Ken Byrne of the School of Natural Sciences in the University of Limerick, said much more forest had to be planted and peatlands restored to serve as carbon stores.
Climate action minister Richard Bruton has announced plans to plant 440million trees by 2040 but Dr Byrne said it was of concern that repeated government targets for increasing tree cover were not achieved.
He said farmers showed little appetite for planting trees and often cited the restraints of the Forestry Act which stated that once land was put in forestry, it could not be changed to other uses, but he said calls to allow some deforestation to return choice to landowners should not be heeded.
“That would be like turkeys voting for Christmas,” he said, warning that tree cover could fall even further.
Dr Byrne urged patience and understanding around the controversial peat-cutting and peat restoration issues.
“My father worked for Bord na Mona all his life and when he hears people say peat removal should never have been allowed, he tells me that’s all very well but it put you through college and kept me off a boat to Australia, so I have perspective about it.”
He said increasing the pace at which peatlands were preserved and drained peatlands were allowed to refill with water would restore much of their carbon storage capacity.
But he added: “It will take 20 years and patience. There is no quick-fix.”
The gathering, hosted by the Irish Creamery Milk Suppliers Association, also heard from economist Cathal Buckley who said the diary sector faced difficult choices. Farmers were getting more milk per cow and reducing carbon emissions per kilogram of milk but those efficiencies were being overtaken by the increase in actual herd numbers. “That’s the conundrum,” he said.
Pippa Hackett, Green Party spokesperson on agriculture, lives that conundrum every day as she is also a farmer, although in cattle and sheep.
“The take-home message for me is that all the efficiencies in the world aren’t going to effect any change in absolute emissions if we keep increasing the numbers on the ground,” she said.
Economist Colm McCarthy said there may be some good news for Irish farmers in future as he believed the penalties for carbon production would eventually switch from the producer to the consumer.
He said there was no logic in the current arrangement where Irish farming was held liable for its carbon emissions when much of its produce was consumed abroad, whereas Saudi oil producers were not held liable for their emissions of their fuel products. That burden fell instead on the motorist.
Such a change would increase food prices and reduce market but he said younger people were already moving away from animal-based diets. Irish farmers had little to fear as they had a quality product that could sell at a premium.
“There’s nothing wrong with having a higher share of a smaller market,” he said.
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